         (atomic/set! canceled true)))))
 
 (defn- proxy-subscriber
+  "Create a proxy subscriber.
+  The main purpose of this proxy is apply some
+  kind of transformations to the proxied publisher
+  using transducers."
   [^Publisher p xform subscriber]
   (let [rf (xform (fn
                     ([s] s)

          (.onComplete subscriber))))))

(defn- subscribe-once
  [^Publisher p callback]
  (let [subscription (atomic/ref nil)
        completed (atomic/boolean false)

          (async/close! requests))))))

(defn- promise->subscription
  "Coerce a promise instance to an instance
  of subscription interface."
  [subscriber source]
  (let [canceled (atomic/boolean false)
        completed (atomic/boolean false)]
